Twenty-four new species of the caddisfly genus Polycentropus (Insecta: Trichoptera: Polycentropodidae) occurring in Brazil are diagnosed, described, and the male genitalia of each are illustrated. Eighteen of the new species are placed in the Polycentropus jorgenseni species complex of the Polycentropus gertschi group of New World Polycentropus sensu lato. Furthermore, 6 new species within the P. gertschi group (P. ancistrus, sp. n., P. boraceia, sp. n., P. carioca, sp. n., P. froehlichi, sp. n., P. galharada, sp. n., and P. graciosa, sp. n.) are placed in an informal diagnostic cluster of species with P. urubici Holzenthal and Almeida. Ten of the other P. gertschi group species form a second cluster of diagnostically similar species, the Polycentropus soniae cluster (P. caaete, sp. n., P. carolae, sp. n., P. cheliceratus, sp. n., P. fluminensis, sp. n., P. itatiaia, sp. n., P. minero, sp. n., P. santateresae, sp. n., P. soniae, sp. n., P. tripui, sp. n., and P. virginiae, sp. n.). Two of the remaining 8 new species are included in the P. jorgenseni species complex (P. cipoensis, sp. n. and P. verruculus, sp. n.), while the remaining 6 are unique and cannot be placed in one of the groups at this time (P. acinaciformis, sp. n., P. amphirhamphus, sp. n., P. cachoeira, sp. n., P. inusitatus, sp. n., P. paprockii, sp. n. and P. rosalysae, sp. n.).